Does node.js support the 'let' statement?

If not, is there a way to duplicate the functionality with a self-executing anonymous function or something?

And/or is there another js environment that

has

let

and and

has a REPL, as node does? Rhino?

EDIT:

This question was asked quite a while ago. As of now, late 2015, the answer is "Yes, yes it does". Harmony features were included by default in io.js 3.3, and have been recently brought back to node.js with the 4.x release.